Hip fracture is the most serious consequence of osteoporosis, and over 90% of hip fractures in women are the result of a fall. Falling accounts for the majority of deaths related to injury, and is a major cause of morbidity and disability in the elderly. Those who survive falls may have restricted activity, soft-tissue injuries, or fractures. However, the cause(s) of most falls is not known. Only a handful of studies on the epidemiology of falls have been population-based, and of these, most have investigated the contribution of only a few risk factors. We propose to study the relationship between major known and hypothesized risk factors for falls in a population-based sample of approximately 1,000 community-dwelling men and women 67 years of age and older. The association of these risk factors and falls, retrospectively (i.e. a history of falls) and prospectively, will be assessed. Specifically, we propose to determine the independent contributions of individual risk factors including brain abnormalities identified by magnetic resonance imaging (MRI), abnormalities of gait, balance and neuromuscular function, medication use, orthostatic hypotension, cognitive and physical functioning, to subsequent risk of falls. Potential MRI abnormalities include gray and white matter changes, ventricular enlargement and stroke. We will also relate MRI abnormalities to other risk factors for falls such as abnormalities of balance, gait and neuromuscular function, and levels of plasma testosterone and estrone. The proposed research questions will be investigated in an ancillary study to an ongoing NHLBI-sponsored prospective study of cardiovascular diseases in an elderly population: The Cardiovascular Health Study (CHS). This partnership, where most risk factors are already obtained as part of CHS, affords an extremely cost-efficient study. The proposed study will add new knowledge about risk factors for falls, and thus to the most serious consequence of osteoporosis: hip fractures resulting from falls.